Mail attachments saved as links to mail.app folders

I’m evaluating EagleFiler for archiving emails. It looks really good but I don’t understand how mail attachments are saved. When I click on attachments in EagleFiler, it opens the original email in mail.app. I thought the attachments would be saved in EagleFiler as well.

I might be missing something, any clarification would be appreciated!

The attachments are saved in EagleFiler, and when you open the e-mail from EagleFiler, Mail will display EagleFiler’s copy of the message and its attachments.